JPH0341303A - Scanning type tunnel microscope - Google Patents

Abstract

PURPOSE:To enable attainment of high resolution by a construction wherein a sample stage holding a sample and a piezoelectric element driving mechanism driving a probe are disposed on a support block and the sample is moved slightly by a precise slight-motion mechanism. CONSTITUTION:The inside of an observation chamber 1 is put in a state of high vacuum or ultra-high vacuum by exhaustion by an exhausting device. A base board 20 constructed integrally with a flange 19 is inserted into the observation chamber 1 from the lateral side of the observation chamber, and vibration removing devices 7 are disposed on the base board 20, while a support block 2 is disposed on the vibration removing devices 7. A probe socket having a probe 4 is fitted removably to the fore end of a probe driving mechanism 3. Besides, a sample holder is fitted removably to a sample stage 5. A precise slight-motion mechanism which moves a sample slightly within an X-Y plane vertical to the direction Z when the direction of the height of the probe 4 and a sample surface is set in the direction Z is provided at the sample stage 5. Since a slight motion is prevented from being propagated to a microscope through a mechanism for moving the sample, etc., according to this constitution high resolution can be obtained in observation of the sample.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a scanning tunneling microscope that detects a tunneling current by bringing a probe close to a sample and outputs an image of irregularities on the surface of the sample.

[Prior art and problems to be solved by the invention] In a scanning tunneling microscope that detects a tunnel current by bringing a probe close to a sample and driving it three-dimensionally, the probe tip and It is necessary to bring the distance between the sample surface and the sample surface close to about 1 nm. Therefore, even a slight vibration may cause contact between the sample and the tip of the probe, resulting in damage to the atomic tip of the probe or damage to the sample.

Since atomic-level resolution cannot be obtained with a probe with such a damaged atomic tip, in a scanning tunneling microscope device, a vibration isolator is installed between the device and the installation surface to remove vibrations from outside the device. is arranged to regulate the vibration of the probe and sample.

However, if the mechanism for moving the sample is introduced from outside the observation room where the scanning tunneling microscope is installed, vibrations from outside the device will be transmitted to the scanning tunneling microscope through the mechanism, causing problems as described above. The problem arises that accurate resolution cannot be obtained.

The present invention takes the above-mentioned problems into consideration and aims to provide a scanning tunneling microscope that can obtain high resolution.

[Means for Solving the Problems] The present invention provides a scanning tunneling microscope that detects tunneling current by bringing a probe close to a sample and driving it three-dimensionally. A piezoelectric element drive mechanism is placed on a base, and when the height directions of the probe and the sample surface are two directions, the sample is slightly moved in the XY plane perpendicular to the Z direction or in the Z axis direction. The present invention is characterized in that it is provided with a precision fine movement mechanism and a drive shaft for driving the precision fine movement mechanism, and the drive shaft is provided so as to be separable from the precision fine movement mechanism.

[Embodiments] Hereinafter, embodiments of the present invention will be described based on the drawings. 1st
The figure is an apparatus configuration diagram (plan view) for explaining one embodiment of the present invention, FIG. 2 is a view taken along arrow A-A in FIG. 1, and FIG. 3 is a diagram for explaining the sample fine movement mechanism. be.

In Figures 1 and 2, 1 is an observation room, 2 is a base, and 3
is a probe drive mechanism, 4 is a probe, 5 is a sample stage, 6 is a sample holder, 7 is a vibration isolator, 8X is an X drive shaft, 9X is a lever,
8y is the Y drive shaft, 9y is the lever, 10 is the pin, 11X and 11y are the magnetically coupled rotation introducers, 12x is the X rotation axis, 1
2y is 7 rotation axis, 13X and 13y are joint, 14
is the introduction rod, 15 is the arm, 16 is the stop ring, 17
is a bearing, 18 is a bellows, 19 is a flange, 20
is the bottom plate, and S is the sample.

In FIG. 2, the inside of the observation chamber 1 is evacuated to a high vacuum or ultra-high vacuum state by an exhaust device (not shown). A bottom plate 20 integrated with a flange 19 is inserted into the observation chamber 1 from the side of the observation room, and a vibration isolator 7 is disposed on the bottom plate 20. A base 2 is arranged.

A probe drive mechanism 3 and a sample stage 5 are arranged on the base 2. A probe socket having a probe 4 is detachably attached to the tip of the probe drive mechanism 3. Further, a sample holder 6 is detachably attached to the sample stage 5.

Here, when the height direction of the probe and the sample surface is defined as the Z direction, the sample stage 5 is provided with a precision fine movement mechanism for finely moving the sample within the XY plane perpendicular to the Z direction. FIG. 3 shows a configuration diagram of the precision fine movement mechanism. In Fig. 3, 30 is a support, 31 is a sample moving table, 32x, 32y, and 33 are levers, 34, 35, 36 are bearings provided on the drive contact surface of the moving table 31, and 37 is provided on the moving table. This is a spring that applies force so that each bearing always contacts the point of action and fulcrum of each lever with the same force.

In the figure, levers 9x and 9y are pushed by drive shafts 8X and 8y introduced from a direction parallel to the Z axis perpendicular to the paper surface. (See FIG. 1) Now, when the drive shaft 8X is rotated and moved by one pitch and the lever 9X is pushed, the lever 32x that is in contact with the point of action of the lever 9X is pushed. Applicable lever 32
x reduces the amount of movement according to the ratio of the force point-fulcrum distance and the fulcrum-point distance, that is, the lever ratio, and moves the center of the moving stage 31 (the center of the sample holder 6) in one direction of X-X. .

Similarly, when the drive shaft 8y is rotated and moved by one pitch, the center of the moving table 31 is moved in the Y-Y direction by an amount corresponding to the leverage ratio.

Here, if the sample holder is heated to about 1200° C. by energizing the sample holder using a heating device (not shown), the movable table 31 will swell evenly from the center of the movable table, that is, on the Z axis. The moving table has bearings 34, 35, 36
Since the levers 32x, 32y and the fulcrum 33 are in contact with the levers 32x, 32y and the fulcrum 33 via the levers 32x, 32y, and the fulcrums o, p and the fulcrum 33 of the levers 32x, 32y are provided on the support 30, thermal expansion and contraction of the moving platform is prevented. Since the result is virtually the same as if the sample was supported at the center of the sample moving table (on the Z axis), the drift caused by the thermal expansion and contraction does not occur.

Now, in order to drive the sample S placed on the sample holder 6 to a desired position by the above-mentioned fine movement mechanism, the drive shafts 8x and 8y of the sample stage and the drive shafts introduced from outside the observation chamber via the flange are required. Rotation axis 12x of rotation introducer
, 12y must be connected. In the present invention, in order to prevent vibrations from being transmitted to the scanning tunneling microscope via the rotating shaft of the rotating introducer introduced from outside the observation room, the drive shaft of the precision drive mechanism and the rotating shaft of the rotating introducer are are provided so that they can be separated.

1 and 2, the drive shaft of the precision drive mechanism and the rotation shaft of the rotation introducer are shown separated.

In the figure, joints 13x and 13y are provided at the tip of the rotating shaft of each rotation introducer, and a flat portion 4 is provided at the tip of the rotating shaft, and the flat portion 40 is located inside the joint. It is held between rollers 4], a, and 41b provided at.

Therefore, the joint is configured to be slidable along the flat portion (in the Z-axis direction), and the joint 13x,
], 3y or rotating shafts 12x, 12y.

In addition, the moving rod 14 is inserted from the outside of the observation room via the flange 19.
The introduction rod 14 is introduced by being screwed into a threaded portion provided on the flange. An arm 15 is loosely fitted to the tip of the moving rod 14 via a stop ring 16, and a bearing 17 is rotatably attached to the tip of the arm 15. The bearing 17 is connected to the joint 13 at the tip of the rotating shaft of each rotation introducer.
They are fitted into grooves 17a provided on the circumferential surfaces of x and 13y. Therefore, by rotating the moving rod and moving it in the direction of insertion into the observation chamber, the joints 13x, 13
y is moved, and the slots 42 provided in the joints 13x and 13y are connected to the pin 1 provided at the end of the drive shaft.
0. In this way, the magnetic coupling type rotation introducer 11
By rotating the magnets 43a and 43b of the sample fine movement mechanism, the sample attached to the sample stage is moved. After moving the sample to a desired position, when performing observation using a scanning tunneling microscope, the joint 13 is moved by rotating the moving rod 14 in the direction of pulling it out of the observation chamber.
X.

], 3 y is also moved in the same direction, and the rotating shaft and the driving shaft are separated at the same time. This prevents vibrations from being transmitted to the scanning tunneling microscope from outside the observation room, making it possible to obtain high resolution in sample observation using the scanning tunneling microscope.

Note that the above-described embodiment is only one embodiment of the present invention, and the present invention can be implemented with various modifications. for example,"
In the two consecutive embodiments, the precision fine movement mechanism for moving the sample stage in the XY plane perpendicular to the Z axis is
Although the drive shaft and the X and Y rotation axes of the rotation introducer are provided so as to be able to be separated at the same time, the present invention provides a fine movement mechanism for moving the sample stage in the Z-axis direction and its Z drive shaft.
A rotation introducer and two rotation axes are provided parallel to the X and Y rotation axes to rotate the Z drive shaft, and the Z drive shaft and the two rotation axes are connected to the X and Y rotation axes. It may also be provided so as to be separable at the same time as the drive shaft and the X and Y rotation axes.

[Effects of the Invention] As is clear from the above description, according to the present invention, in a scanning tunneling microscope that detects tunneling current by bringing a probe close to a sample and driving it three-dimensionally, the sample is held. A sample stage for moving the sample and a piezoelectric element drive mechanism for driving the probe are arranged on a base, and when the height direction of the probe and the sample surface is defined as the Z direction, in the XY plane perpendicular to the Z direction. or a precision fine movement mechanism that finely moves the sample in the Z-axis direction;
By providing a drive shaft for driving the precision fine movement mechanism and by providing the drive shaft so that it can be separated from the precision fine movement mechanism, vibrations are not transmitted to the scanning tunneling microscope through the mechanism for moving the sample, etc. Therefore, high resolution can be obtained when observing a sample using a scanning tunneling microscope.

[Brief explanation of drawings]

Fig. 1 is an apparatus configuration diagram (plan view) for explaining one embodiment of the present invention, Fig. 2 is a view taken along arrow A-A in Fig. 1, and Fig. 3 is a diagram for explaining the sample fine movement mechanism. It is a diagram. 1: Observation room 2: Base 3: Probe drive mechanism 4: Probe 5: Sample stage 6: Sample holder 7: Vibration isolator 8x: X drive axis 8y: Y drive axis 9x, 9y: Lever 10: Pin 11x , lly: Magnetic coupling type rotation introducer 12x: X rotation axis 12y: Y rotation axis 13x, 13y: Joint 14: Introduction rod 15: Arm 16: Stop ring 17: Bearing 18: Bellows 19: Flange 20: Bottom plate S :sample

Claims (1)

[Claims] In a scanning tunneling microscope that detects tunneling current by bringing a probe close to a sample and driving it three-dimensionally, a sample stage that holds the sample and a piezoelectric element drive mechanism that drives the probe are arranged on a base. and a precision fine movement mechanism for finely moving the sample in an XY plane perpendicular to the Z direction or in the Z axis direction, when the height direction of the probe and the sample surface is the Z direction, and driving the precision fine movement mechanism. Along with providing a drive shaft,
A scanning tunneling microscope characterized in that the drive shaft is provided so as to be separable from the precision fine movement mechanism.